Heart/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby. The sound of a heartbeat is heard as Tim and Moby are standing side-by-side in a room with green walls. Tim is dressed in a tuxedo and a bowtie. TIM: So, I … hear you have a letter for me. MOBY: Beep. TIM: Ooh, a love letter! And it’s not even Valentine’s Day! Moby hands Tim a pink envelope with heart stickers on it. MOBY: Beep. TIM: Of course it’s a Valentine! Look at the envelope! Tim takes the letter out of the envelope. TIM: Oh. Tim reads from the typed letter. TIM: Dear Tim and Moby, Sometimes when I’m playing hockey, my heart beats so loud that I can hear it. What's that all about? From, Lana. (Junction City, Kansas) TIM: Right, hearts, cause the letter was about the heart. Moby raises his arm and pats Tim on the back to console him. TIM: All right, all right. This is an important question, so I want to be sure we understand a few things about the heart. The heart is a powerful muscle in your chest, about the size of your fist. A white cutout of a human body, a human heart, and a closed human fist appear on screen. The heart and the fist are nearly identical in size. TIM: The heart muscle is different from other muscles. It never gets tired, and it pumps blood through your body so that oxygen and nutrients can get to the organs and tissue that need them, and so that cell waste products can be removed. The fist disappears and the white cutout of the human body moves behind the heart. Red dashed lines emanate from the heart to the extremities and the head of the cutout, representing the flow of blood away from the heart. Blue dashed lines move from the ends of the extremities and the head to the heart, representing the flow of blood toward the heart. TIM: The heart is made up of two pumps, one on the left side, and one on the right. Each of the pumps is made of an atrium and a ventricle. A simplified graphic of a cross-section of the heart appears, showing the two halves of the heart. A flashing arrow on each side points to the top part of each half of the heart, which are the atria. Flashing arrows then point to the two bottom sections of the heart, the ventricles. The arrows on the left side point to used, deoxygenated blood, and the arrows on the right side show fresh, oxygen-rich blood. TIM: The atria bring blood back into the heart and pass it to the ventricles, which pump the blood back out. An animation shows blood passing through the smaller tubes that lead into the two atria. The blood enters the atria through a valve at the top of each atrium, and moves down into the ventricles after the valve between each atrium and each ventricle opens. The valves on the atria then close. Valves leading out from the ventricles then open, and the blood exits the heart through two larger tubes located at the top center region of the heart, next to the atria. After all the blood exits through the valves, the valves close. TIM: This pumping cycle produces your heartbeat. Here's how it works: When your brain sends a signal for the heart to beat, the right atrium fills with used blood that has been through the body and needs to go to the lungs for more oxygen. An animation shows the process that Tim describes. TIM: The left atrium fills with fresh blood from the lungs that is ready to go back through the body. A red arrow appears on the right side of the screen, pointing at the heart’s left atrium, which is on the right side of the screen for anyone viewing the video. The heart’s left atrium fills with the new blood. TIM: The atria squeeze blood to the ventricles below. When all the blood is in a ventricle, the valve between the ventricle and atrium closes, and the ventricle pushes the blood out of the heart. An animation shows the old and new blood squeezing from each of the atria, through a valve, and down into the ventricles. The ventricles expand in size as the blood rushes into them. The valves from the atria to the ventricles close, and then the blood exits through the valves between the ventricles and the larger central tubes. TIM: The right ventricle pumps old blood to the lungs. An animation shows the white cutout of the human again. A heart and lungs appear inside the cutout. They are attached to branched tubes leading to a single tube, the trachea, or windpipe. The trachea leads to the mouth area of the head. The lungs expand and contract to depict breathing, and change in color to blue to depict the old blood that is being pumped into them from the right ventricle. The heart expands and contracts to depict pumping the blood. TIM: The left ventricle pumps fresh blood into your body so it can circulate. The video shows the white cutout turning red to depict the fresh blood being pumped throughout the body. TIM: It takes about one minute for blood to circulate through your entire body and back into the heart to be pumped out again. The screen returns to Tim and Moby in their room. This time, Moby is standing behind Tim, secretly writing on a piece of pink paper while Tim is speaking. TIM: So, now we know how your heart beats. A heartbeat sound is heard as a human heart is shown beating.' '''TIM: The process of pumping blood is one that your body does automatically over and over again, no matter what you’re doing. Animations show Tim's heart beating as he performs the various activities of his daily life. MOBY: Beep. TIM: Right. Lana asked about feeling her heart beat during sports. Your heart rate increases when you run and play, and even when you're nervous. Think about it; when your body is working hard the muscles tire out quicker. Your heart has to beat faster to get oxygen through your body so that you can keep going. The faster and harder your heart is beating, the louder it sounds. An animation shows the white cutout with its heart in its chest. The heart expands and contracts as it beats. The cutout repeatedly raises and lowers its arms, depicting exercise. The longer and faster the cutout exercises, the faster the heart contracts and expands. TIM: Well, I … um … hope that answers your question, Lana. Moby, with a friendly smile on his face, looks Tim, and holds up the pink letter. His lights flash as he waves the letter up and down. MOBY: Beep! TIM: Another one? Tim holds the letter, which reads: “Dear Tim, You are nice and I like you. You are a good pal. Signed, Moby.” A rudimentary drawing of a heart is next to Moby’s name. TIM: Awww. Category:BrainPOP Transcripts Category:BrainPOP Health Transcripts